Mutiple secondary transformer.



No. 76'7,497 PATENTED AUG. 16, 1904 LS. PEOK & 0. LE G. PORTESOUE.

MULTIPLE SECONDARY TRANSFORMER.

APPLICATION FILED AUG. 8, 1903. I no MODEL. 1 '2 SHEETS-SHEET 1.

6 WITNESSES: 46% wif'im Cid m No 767,497. Y PATENTED AUG. 16, 1904. J.s. P501: & 0. LB G. FORTESGUE.

MULTIPLE SECONDARY TRANSFORMER.

APPLICATION IILED'AUG. a, 1903.

Fig 5 2 SHEETS-SHEET 2.

WITNESSES:

@m I kg, f Q2 ATTOIIPNEY Patented August 16, 1904.

UNITED STATES PATENT OEEIcE.

JOHN S. PEOK, OF PITTSBURG, AND CHARLES LE G. FORTESCUE, OF VVIL-KINSBURG,

PENNSYLVANIA, ASSIGNORS TO WVESTINGHOUSE ELECTRIC & MANUFACTURINGCOMPANY, A CORPORATION OF PENNSYLVANIA.

MULTIPLE SECONDARY TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 767,497, ated A g 16,1904.

Application filed August 8, 1903.

T aZZ whom it may concern.-

vBe it known that we, JOHN S. PEOK, a citi Zen of the United States,residing at Pittsburg, and CHARLES LE G. FORTESCUE, a subject of theKing of Great Britain, residing at VVilkinsburg, in the county ofAllegheny, State of Pennsylvania, have invented a new and usefulImprovement in Multiple Secondary Transformers, of which the followingis [0 a specification.

Our invention relates to apparatus for transforming alternating electriccurrents, and particularly to apparatus of this character which havemultiple secondary windings.

The object of our invention is to provide a transformer for supplying aplurality of independent sets of translating devices in such manner thatvariations in load upon one secondary circuit shall have substantiallyno effect upon the voltage of the other secondary circuit or circuits orin such manner that variations in load upon one of the secondarycircuits have relatively small effect upon the voltage of the othersecondary circuit or circuits.

It is frequently found desirable to supply both motors and lamps from asingle transformer; but on account of the inductive character of themotor-load variations in this load are likely to be productive ofserious varia- 3 tions of the voltage of the lamp-circuit. It

has therefore generally been found impracticable to operate both lampsand motors from the same transformer, since good regulation is necessaryfor satisfactory operation of electric lamps.

'Our present invention avoids the difficulty above stated and isillustrated in the accompanying drawings, in which- Figure 1 is adiagrammatic view of appara- 4 tus embodying and illustrating ourinvention in its simplest form. Figs. 2 and 3 are diagrams similar toFig. 1, but illustrating modifications of the transformer structure.Fig. 4 is a sectional view of a transformer and illustrating onearrangement of the coils with reference to each other and to the coreand showing the circuit connectionsto the generator and to translatingdevices diagrammat- Serial No. 168,751. (No model.)

ically. Fig. 5 is a view similar to Fig. 1, but showing a difierentarrangement of coils. Fig. 6 is a view similar to Fig. 4, butillustrating a core-type transformer. Figs. 7, 8, 9, and 10 are diagramssimilar to Figs. 1, 2, and 3, but illustrating further modifications ofthe transformer-windings.

Our invention as here illustrated consists, generally speaking, inproviding a transformer with independent secondary windings forseverally supplying independent loads which may or may not differ incharacter and in so placing the two windings with reference to theprimary winding that the leakage magnetic field produced by a load uponone circuit will have either no substantial effect upon the voltage ofthe other circuit or one that is productive of a minimum degree ofdisturbance.

As illustrated in Fig. 1, the primary winding 1 of the transformer issupplied with current from a generator 2 and in turn serves to generatecurrents by induction in the two secondary windings 3 and 1, which aresymmetrically located at the two sides of the primary winding, thewinding 3 being shown as supplying lamps 5 and the winding 4 assupplying motors 6.

In Fig. 2 the transformer is shown as provided with two primary coils 7and 8, connected in series and supplied with current by the generator 2.The secondary winding 3, supplying the lamps 5, is here shown asconsisting of a single coil located midway between the two primarycoils, while the secondary winding supplying the motor or motors 6 isShown as comprising two coils 9 and 10, respectively located at thesides of the primary coils 7 and 8.

In Fig. 8 the primary winding supplied by the generator 2 comprises fourequally-spaced coils 11, 12, 13, and 14. The secondary circuit supplyingthe lamps 5 comprises two coils 15 and 16, located between primary coils11 and 12, and two coils 17 and 18, located between primary coils 13 and14, all connected in series. The secondary winding supplying the motoror motors 6 also comprises two coils 19 and 20, located between primarycoils 12 and 13, andtwo coils 21 and 22, located, respectively, besidethe primary coils 11 and 14. i

It is found with the arrangement of windings shown in each of thefigures above described that the leakage magnetic field produced by aload upon one circuit, while it lowers the voltage on its own circuit,has a tendency to slightly raise the voltage on the other circuit, andthis tendency to raise the voltage is very nearly offset by the tendencyto a drop in voltage due to the ohmic resistance of the primary winding,so that changes in'load on one circuit produce substantially no effecton the voltage of the other circuit.

While one of the secondary circuits in the arrangements shown isdesignated as supplying lamps and the other as supplying motors, it isobvious that either circuit maybe used for the lamps and the other forthe motors, since the windings are symmetrically located with referenceto the primary coils.

In Figs. 1, 2, and 3 the coils are all shown as arranged parallel toeach other and adapted for embodiment in transformers of the shell typeof construction. Another arrangement of coils which is satisfactorilyoperative in accordance with our invention, but which has lessstructural simplicity than the forms already described, is shown in Fig.4. In this arrangement the secondary winding 23 for supplying the lamps5 is located between and parallel to two primary windings 24 and 25, theaxes of the three coils being substantially coincident. The secondarywinding for supplying the motor or motors 6 is shown as comprising asingle coil 26, the axis of which is also coincident with the axes ofthe two primary coils and the other secondary coil and the said coilbeing also concentrically disposed around the other coils.

In the form of transformer shown in Fig. 5 the primary winding comprisestwo concentric coils 27 and 28, and the secondary winding supplying thelamps 5 is shown as comprising four coils 29, 30, 31, and 32, the coil29 being outside and the coil 32 inside both primary coils and the coils30 and 31 being located side by side between the two primary coils. Thesecondary winding for supplying the motors is here shown as comprising,two coils 33 and 34, which are parallel to each other and the axes ofwhich coincide with those of the primary and the other secondary coils,but which are formed as flat coils and located at the respective ends ofthe other coils, the secondary coils for supplying the lamps and theprimary coils being concentrically arranged.

It will of course be understood that the number of coils. and theirrelative arrangements may be greatly varied from what is here shown andthat the primary and secondary windings may be interlaced to as great anextent as may be desired.

Our invention is adapted to transformers of the core type aswell as tothose of the shell type, and this is indicated in Fig. 6, in which eachside arm of the core 35 is provided with two primary coils 36 and 37,between which is located a secondary coil 38 in parallel relation withthe coils 36 and 37 and with its axis coincident with the axes of saidcoils. The two. coils 38 are herev shown as connected in series witheach other to supply the lamp-load 5. The winding for supplying themotor or motors 6 is here shown as comprising two coils 39, each ofwhich surrounds one of the side portions of the core 35 and is locatedconcentrically within the primary coils 36 and 37 and the secondary coil38, these two coils being connected in series for supplying the motor ormotors;

In Figs. 7, 8, 9, and 10 we have shown other forms oftransformer-windings the secondaries of which are intended to supplyboth lamps and motors, so that changes in load on mary circuit, so thatthe magnetic leakage between the lamp-winding and the primary windingwill be reduced to a minimum and will be less than the magnetic leakagebetween the motor-winding and the primary winding. With thesearrangements of windings the motor and lamp loads are notinterchangeable with reference to the two circuits.

In Fig. 7 the primary winding 40 is shown as comprising a single coiland the secondary winding as comprising four coils 41, 42, 43, and 44,all connected in series, the motor or motors 6 being connected acrossthe outside terminals of the coils 41 and 44 and the lamps 5 beingconnected to the outer terminals of the coils 42 and 43.

In Fig. 8 the primary winding 45 is indicated as a single coil, and thesecondary windings 46, 47, 48, 49, 50, and 51 are shown as connected inseries, the motor or motors 6 being connected to the outside terminalsof the coils 46 and 51 and the lamps 5 and 5 being shown as connectedbetween the outer terminals of coils 47 and and the neutral or balancingconductor 52, which is in turn connected to the outer terminals of thecoils 48 and 49. The inner terminals of the coils 48 and 50 areconnected together, and the inner terminals of the coils 47 and 49 arealso connected together, the arrangement being such as to permit ofunbalancing the load on the three-wire circuit without unbalancing thevoltage.

In Fig. 9 the primary winding is shown as comprising two coils 53 and54, the secondary circuit supplying the motor or motors 6 as comprisingthree symmetrically-located coils 55, 56, and 57, all connected inseries, and the an ill lllllll ll an ll'lll lllll cm s o 59, 60, and 61,all symmetrically disposed with reference to the primary winding andconnected in series independently of the windings which supply the motoror motors.

In Fig. 10 we have indicated a single primary winding 62 and a secondarywinding for supplying the motor or motors 6, comprising two coils 63 and64, which are disposed with reference to the coils 65 and 66, whichsupply the lamps 5, and with reference to the primary winding 62 thesame as the corresponding coils, (shown in Fig.'7,) except that the twosecondary windings are here entirely independent of each other. Althoughthe two sets of secondary coils are located at different distances fromthe primary coil or coils, the adjustment of magnetic leakage, ashereinbefore pointed out, is such as to insure reasonably satisfactoryregulation, provided the secondary coils that are more remote from theprimary winding are utilized for supplying the inductive load.

It will be understood that a very large number of combinations of coilscould be made which would afford substantially the results secured bymeans of those here specifically illustrated, and we therefore desire itto be understood that our invention is to be construed to cover all suchcombinations and arrangements of coils as will permit of the operationof separate sets of translating devices in such manner that variationsin load upon one circuit will produce either no effect or a minimumeffect upon the voltage of the other circuit. It will also be understoodthat the number of secondary circuits may be greater than two and thatthey may carry the same kind of load, if desired; that the invention maybe embodied in multiphase as well as in single-phase transformers ofeither the core type or the shell type, and that all of the combinationsof coils here shown and described may be embodied in transformers ofeither the shell or the core type.

We claim as our invention 1. A transformer having a plurality ofsecondary windings the coils of which are symmetrically disposed withreference to the primary coils and to each other to avoid interferingleakage magnetic fields, whereby a variation in load on one of, thesecondary circuits has substantially no effect on the voltage of anothersecondary circuit.

2. A transformer having a plurality of secondary windings the coils-ofwhich are symmetrically disposed with reference to the primary coils andto each other to avoid interfering leakage magnetic fields so that wheneither or any of the separate secondary windings is employed to supply aload differing in characlllllllltldial... will..

windings, a variation in the load on one circuit will have substantiallyno effect on the voltage of another circuit.

3. A transformer having a plurality ofsecondary windings the coils ofwhich are symmetrically disposed with reference to the pri- .metricallydisposed with reference to each other and to the primary winding but atdifferent distances from said primary winding, so that the magneticleakage between one secondary winding and the primary winding will beless than that between another secondary winding and the primarywinding.

5. A transformer having a plurality of secondary windings the secondarycoils being symmetrically disposed with reference to each other and tothe primary coils but at different distances from said primary coils, sothat the magnetic leakage between one secondary winding and the primarywinding will be less than that between another secondary winding and theprimary, the former secondary winding being employed to supply loadsrequiring accurate voltage regulation and the latter to supply loadswhich are affected to a less degree by voltage fluctuations.

6. In a transformer for supplying both inductive and non-inductiveloads, the non-inductive load being supplied from a three-wire circuit,secondary coils connected in series and symmetrically disposed withreference to each other and to the primary coils but at differentdistances from said primary coils, so that a variation in load on theinductive secondary circuit has relatively small effect on the voltageofthe non-inductive secondary circuit and so that an unbalancednon-inductive load on the three-wire circuit does not materiallyunbalance the voltage thereof.

7. A transformer for supplying two circuits which has its secondarycoils for supplying the respective circuits symmetrically disposed inunlike manner with reference to the primary coils, whereby the voltageof each circuit is substantially unaffected by variations in the loadon, the other circuit.

In testimony whereof we have hereunto subscribed our names this 31st dayof July, 1903.

JOHN S. PEUK. CHARLES LE G. FORTESOUE.

Witnesses:

HONORIA L. DOUGHERTY, BIRNEY HINES.

